This invention is directed to a leg apparatus which can be utilized as a supporting leg to support a magnetically levitated vehicle vertically and as a guide leg to guide mechanically the vehicle along a guideway side wall, and furthermore an improved guide leg apparatus while in turn guides mechanically the vehicle when the magnetically levitated vehicle is not supported the sufficient lateral guide which is levitated by a magnetic force. The invention is more particularly concerned with a leg apparatus in which wheels are supported by a shaft of a fork arm in a lever-type hanger component. An expandable lifting actuator is attached to another arm of said hanger to retract wheels completely, and a damper is provided to said lifting actuator in series acting as a shock buffer, so that the structure of the leg apparatus can be simple and light weight with a small storage space and easy maintenance. The invention is concerned also with a leg apparatus for the magnetically levitated vehicle in which a stopper ring apparatus is separately positioned to guide the vehicle along the guideway side wall in lieu of the guide leg apparatus in a case when the guiding apparatus malfunctions, or in an emergency when the vehicle suddenly loses its magnetic force while levitating at high speed, so that the leg apparatus can be retracted and stored the guide leg of the high speed running vehicle. As a result, the running resistance and noise can be reduced, and a system can be constructed with a compact and light weight structure of the storage space.
With a magnetically levitated vehicle system, the ground coil is arranged on the ground for levitation and propulsion functions and the electrical magnets arranged on the vehicle move by forming a continuously moving magnetic field being corresponded to successive excitation of the propulsion coils. At the same time, by moving electrical magnets on the vehicle, the inductive current is generated in the levitating coil on the ground by which the magnetic field is repulsed, resulting in floating the vehicle.
However, only when the sufficient speed is attained on the vehicle, the inductive magnetic levitating force generates enough power to support the full weight of the vehicle; as a result additional wheels are required to support the vehicle at a low speed cruising.
Such a supporting apparatus with wheels should operate the vehicle comfortably when the vehicle is at rest or at necessitated low speed range; while at high speed, it should be retracted and stored into the vehicle body. Furthermore, when wheels are needed, they should be extended from the vehicle body and a certain mechanism is required to absorb the shock while the wheels are in an extending position.
A prior art leg supporting apparatus employed in a magnetically levitated vehicle (Tokkai-Sho No. 63-212165) disclosed the structure in which wheels were supported by a trailing arm, on which a damper was installed to absorb shocks. Furthermore, a lift cylinder was installed at a pivot side of said damper to retract wheels under actions of lifting the damper and said trailing
The aforementioned supporting leg composed of the lifting cylinder, a buffering mechanism, and the trailing arm requires a larger storage space and a longer maintenance time to service many parts at various locations.
Moreover, while the vehicle is at rest or running at low speed, because the lateral guide by magnetic force is not sufficient enough and a directional control is not sufficiently achieved in order to guide the vehicle mechanically rather than magnetically, a pair of the guide leg apparatus that contacts and rotates against the guideway side wail is installed at both sides of the vehicle.
On the magnetically levitated vehicle, in addition to the guide leg, a stopper ring mechanism is provided at both sides of the vehicles to guide the vehicle safely until a full stop position is attained. Said stopper ring mechanism has a two-fold function. Namely, the first function is to absorb the shock which might be generated by touching against the guideway side wall due to the vehicle's malfunctions while travelling at the high speed of 500 km/h. The second function is to withstand the high load of the lateral force of about 8 tons as a result of the contact with the guideway side wall. Hence, it is required that said stopper ring mechanism is equipped with the shock absorbing system that buffers the shocks, and bearings that can withstand the high load and high speed rotational force.
In a conventional type, as seen in FIG. 13, the stopper ring mechanism is assembled in the aforementioned guide leg apparatus on a same shaft sharing with the guide wheel 60. The buffer system also functions as the oleo apparatus to extend and retract the guide legs, and the bearing is axially supported by a single plain bearing at the center of the stopper ring 61.
Since the guide wheel 60 is not needed any more when the vehicle moves at high speed under a magnetically controlled guide, it is desirable that the guide leg apparatus can be retracted into the storage area of a truck to minimize the running resistance and running noise as well.
However, when magnets are in malfunction while the magnetically floated vehicle is cruising, the stopper ring 61 must protect the vehicle from crushing against the guideway side wall, so that a position of the wheel must always be projected from the truck to some extent. Therefore, according to the above structure, the guide wheel 60 can not be retracted while the vehicle is magnetically levitating.
In the conventional type of the guide leg apparatus, being coaxially installed with the stopper ring mechanism, the guide wheel and the stopper ring are installed together on the same shaft. Consequently, the guide wheel cannot be retracted into the storage space of the truck even when the vehicle is magnetically levitating at high speed without the need of mechanical guide through the guide wheel, causing undesired increments in the running resistance and running noise.
Furthermore, when a guide leg system having retracting and extending functions for legs is designed with such a structure that can withstand the high load and high speed running conditions when magnets malfunctions, the guide leg apparatus itself will become heavier. This is a major technical drawback associated with this type of design.
A magnetically levitated vehicle which is intended to be put into practical use in future will have the maximum speed of 550 km/h, and the lateral force at this speed is about 8 tons. Hence, the plain bearing of the conventional type of the stopper ring apparatus will be instantaneously seized and become to be non-operational.
When magnets malfunctions, the lateral force will be generated and the levitating power will be lost, and the vehicle will then gravitate right and left as it drops downward (the distance between the vertical stopper and the rail is about 140 mm), causing contacts of the stopper ring with the guideway side wall.
Namely, the stopper ring does not contact with the side wall perpendicularly, but with about 2 degrees incline, so that once the aforementioned enormous lateral force is generated, a torque around the shaft of the stopper ring will also be generated. Therefore, the stopper ring must have a strength which is high enough to withstand this torque force. From this point of view, the conventional structure cannot withstand this abnormal situation.